The instant invention relates generally to telephone exchange systems and telephone voice mail systems, and in particular to an integrated telephone switching apparatus which allows multiple remote and/or local telephone exchange systems, such as private branch exchanges (PBX), key systems, central office switches, and CENTREX systems, to be connected to a single voice mail system with full integration of all telephone exchange systems from all locations.
Telephone exchange systems provide organizations with the ability link a plurality of incoming trunk lines with a plurality of telephone extensions at the organizations premises. As indicated above, there are many different types of telephone exchange systems, including private branch exchanges (PBX""s), key systems, central office switching systems, and CENTREX systems which can provide switching capabilities. Numerous PBX systems, key systems, central office switching systems, and CENTREX systems are well known and commercially available from a variety of different vendors. In order to provide continuity within the rest of this specification and the claims, the term PBX will hereinafter be utilized as a generic term to describe a generic telephone exchange system, and it is to be understood that the term PBX is intended to include private branch exchanges as well as key systems, central office switches, CENTREX systems, and other types of telephone exchange systems.
Integration of voice mail systems with PBX systems, key systems, etc. is well known in the art. Integration between a PBX and a voice mail system can generally be defined as the ability to automatically exchange call information between the PBX and voice mail system without user input. More specifically, this exchange of information includes providing the identity of the called party so that the voice mail system can select the proper personal greeting (called party ID), return to operator (dial 0), providing message waiting indicator information back to the PBX (MWI), direct call message retrieval (calling party ID), direct reply to messages left by internal callers, and original called party ID on multiple call forward. In out-of-band integration systems call information from the PBX is provided to the voice mail system by a digital connection between the PBX and the voice mail system. Likewise MWI information flows from the voice mail system back to the PBX through the digital connection. In in-band systems, data is provided to the voice mail system by DTMF tones forwarded with the transferred call. MWI information flows back to an in-band PBX by picking up a predefined extension and dialing a set of DTMF tones back to the PBX. The PBX interprets these tones to light an MWI on the called party extension.
In a typical office telephone exchange system arrangement, the office PBX is directly connected to an associated voice mail system wherein the voice mail system provides voice mail functions for that particular PBX. This is an effective arrangement when a company has only one office with one PBX. However, when a company has more than one location, either locally or remotely, each office PBX is usually provided with an associated voice mail system to serve that particular PBX. In order for the separate voice mail systems to communicate, i.e. to exchange messages, voice messages destined for a remote location are stored in a storage device, such as a hard drive, and at a predetermined time, for example once each hour, the voice mail system will connect with the remote voice mail system and transfer the messages. Although the conventional arrangement of providing separate voice mail systems for each PBX functions effectively, there are many obvious disadvantages to such an arrangement.
The first obvious disadvantage is the cost of providing separate voice mail systems for each location. These costs can be broken down into equipment, service, maintenance, management, and connection costs. With regard to equipment, each separate voice mail system is expensive, and accordingly, the costs for providing each location with its own dedicated voice mail system can run into hundreds of thousands of dollars for a company with four or more offices. Included in the initial equipment expenditures is the cost of purchasing multiple power systems to provide both redundant power and back-up power to the voice mail systems in the event of power equipment failure or power outages. Further adding the equipment costs is the cost of spare parts which are usually maintained at each separate site to effect quick repairs in the event of a system failure. Still further adding the already high cost of separate systems is the fact that each separate system must be oversized to accommodate peak usage at that particular location. Accordingly, each location is provided with more storage space and more accessible voice ports than is necessary if the system were fully integrated. With regard to service and interconnection costs, each location carries maintenance costs, service contracts, the costs of maintaining local system administrators to run the separate systems, and inter-system interconnection charges to exchange messages between locations.
Another obvious disadvantages is that voice mail messages bound for off-site locations are not immediately available to the person receiving the message. As indicated above, these message may be parked in a storage device for an hour or more before they are transferred to the remote voice mail system.
The instant invention provides an integrated telephone switching apparatus which is operative for interconnecting a plurality a private branch exchanges, and/or key systems, and/or central office switches, and/or CENTREX systems (hereinafter PBX""s) to a single voice mail system regardless of manufacturer, or location, or communications protocol. In general, the switching apparatus provides a unique switching arrangement for accepting incoming calls and call information from a plurality of voice mail extensions of a plurality of different PBX""s, and for performing cross-connection of all of those calls to a single voice mail system.
More specifically, the integrated switching apparatus includes a plurality of input ports for accepting calls from the voice mail extensions of different PBX""s, a plurality of output ports for directing the calls to a plurality of voice ports of a voice mail system, and a switching circuit for switching the calls from input ports to the output ports. Voice mail extensions can be connected to the integrated switching apparatus by a variety of different means, including but not limited-to voice over data multiplexers for remote PBX""s, direct connection for local (on premise) PBX""s, and off premise extensions (OPX""s) for local (off-site) PBX""s. The switching apparatus further includes a switching control system for controlling the switching of the incoming calls from the input ports to the output ports. The switching control system receives call information from the different PBX""s, either via a separate digital data connection or by DTMF means, matches each set of call information with an associated call, creates a new set of call information for each of the calls when each of the calls is switched from one of the input ports to one of the output ports, and supplies the new set of call information to the voice mail system when the call is switched so that the voice mail system can answer the call and play the required greeting. The key operating feature of the switching control system is the fact that all of the voice mail ports are dynamically allocated during use. In other words, each voice mail port is selected in rotating sequence during operation, rather than having a predetermined order of preference. By dynamically allocating the voice mail ports, the number of voice mail ports can be reduced to about half the number of incoming voice mail extensions. This is a dramatic reduction in the number of voice mail ports over the one to one allocation system used in the prior art systems, and substantially reduces the overall cost of purchase and maintenance during operation. Still further, the switching control system recognizes different call protocols, including SMDI and various DTMF formats, and automatically creates a new call information data packet in a predetermined protocol for each call for use by the voice mail system.
Accordingly, it is a primary object of the instant invention to: provide an integrated telephone switching apparatus which enables multiple PBX""s to be connected to a single voice mail system; the provision of an integrated telephone switching apparatus wherein the number of voice mail ports is about half of the incoming voice mail extensions; the provision of an integrated telephone switching apparatus having a switching control system that dynamically allocates the voice mail ports during operation; and the provision of an integrated telephone switching apparatus having a switching control system that recognizes and receives a plurality of different call information protocols, and which creates a new call information data packet in a predetermined protocol.